Vulnerability-Lookup

FKIE_CVE-2026-45929

Vulnerability from fkie_nvd - Published: 2026-05-27 14:17 - Updated: 2026-06-25 12:43

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: ovpn: fix possible use-after-free in ovpn_net_xmit When building the skb_list in ovpn_net_xmit, skb_share_check will free the original skb if it is shared. The current implementation continues to use the stale skb pointer for subsequent operations: - peer lookup, - skb_dst_drop (even though all segments produced by skb_gso_segment will have a dst attached), - ovpn_peer_stats_increment_tx. Fix this by moving the peer lookup and skb_dst_drop before segmentation so that the original skb is still valid when used. Return early if all segments fail skb_share_check and the list ends up empty. Also switch ovpn_peer_stats_increment_tx to use skb_list.next; the next patch fixes the stats logic.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3e4fbcb4e078915367ba5576cd70d76dbc970f95	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/442915c96a9bff1c7080e2aedabb1c03faa28d81	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a5ec7baa44ea3a1d6aa0ca31c0ad82edf9affe41	Patch

Impacted products

	Vendor	Product	Version
	linux	linux_kernel	*
	linux	linux_kernel	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/io.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3e4fbcb4e078915367ba5576cd70d76dbc970f95",
              "status": "affected",
              "version": "08857b5ec5d91d83e69e40a36554a8c7557b7301",
              "versionType": "git"
            },
            {
              "lessThan": "442915c96a9bff1c7080e2aedabb1c03faa28d81",
              "status": "affected",
              "version": "08857b5ec5d91d83e69e40a36554a8c7557b7301",
              "versionType": "git"
            },
            {
              "lessThan": "a5ec7baa44ea3a1d6aa0ca31c0ad82edf9affe41",
              "status": "affected",
              "version": "08857b5ec5d91d83e69e40a36554a8c7557b7301",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/io.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
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              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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              "versionEndExcluding": "6.18.14",
              "versionStartIncluding": "6.16",
              "vulnerable": true
            },
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  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\novpn: fix possible use-after-free in ovpn_net_xmit\n\nWhen building the skb_list in ovpn_net_xmit, skb_share_check will free\nthe original skb if it is shared. The current implementation continues\nto use the stale skb pointer for subsequent operations:\n- peer lookup,\n- skb_dst_drop (even though all segments produced by skb_gso_segment\n  will have a dst attached),\n- ovpn_peer_stats_increment_tx.\n\nFix this by moving the peer lookup and skb_dst_drop before segmentation\nso that the original skb is still valid when used. Return early if all\nsegments fail skb_share_check and the list ends up empty.\nAlso switch ovpn_peer_stats_increment_tx to use skb_list.next; the next\npatch fixes the stats logic."
    }
  ],
  "id": "CVE-2026-45929",
  "lastModified": "2026-06-25T12:43:33.257",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-05-27T14:17:08.833",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/3e4fbcb4e078915367ba5576cd70d76dbc970f95"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/442915c96a9bff1c7080e2aedabb1c03faa28d81"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/a5ec7baa44ea3a1d6aa0ca31c0ad82edf9affe41"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2026-45929 (GCVE-0-2026-45929)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:17 – Updated: 2026-08-05 12:28

Title

ovpn: fix possible use-after-free in ovpn_net_xmit

Summary

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/3e4fbcb4e07891536…
https://git.kernel.org/stable/c/442915c96a9bff1c7…
https://git.kernel.org/stable/c/a5ec7baa44ea3a1d6…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 08857b5ec5d91d83e69e40a36554a8c7557b7301 , < 3e4fbcb4e078915367ba5576cd70d76dbc970f95 (git) Affected: 08857b5ec5d91d83e69e40a36554a8c7557b7301 , < 442915c96a9bff1c7080e2aedabb1c03faa28d81 (git) Affected: 08857b5ec5d91d83e69e40a36554a8c7557b7301 , < a5ec7baa44ea3a1d6aa0ca31c0ad82edf9affe41 (git)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.18.14 , ≤ 6.18.* (semver) Unaffected: 6.19.4 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/io.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3e4fbcb4e078915367ba5576cd70d76dbc970f95",
              "status": "affected",
              "version": "08857b5ec5d91d83e69e40a36554a8c7557b7301",
              "versionType": "git"
            },
            {
              "lessThan": "442915c96a9bff1c7080e2aedabb1c03faa28d81",
              "status": "affected",
              "version": "08857b5ec5d91d83e69e40a36554a8c7557b7301",
              "versionType": "git"
            },
            {
              "lessThan": "a5ec7baa44ea3a1d6aa0ca31c0ad82edf9affe41",
              "status": "affected",
              "version": "08857b5ec5d91d83e69e40a36554a8c7557b7301",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ovpn/io.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
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                  "vulnerable": true
                },
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        {
          "lang": "en",
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        }
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          },
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            {
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              "value": "AV:L - The vulnerable code is `ovpn_net_xmit`, the netdevice TX path (ndo_start_xmit), triggered by transmitting a packet out the local ovpn tunnel interface; the triggering precondition (a shared skb) is a local TX-side artifact and cannot be induced by a remote peer, whose data flows through the separate RX path.\nAC:L - The attacker controls both sides \u2014 arranging the skb-sharing reference holder and initiating the transmit \u2014 so the use-after-free race is within their control; choosing the higher-severity value where exploitation reliability is uncertain.\nPR:L - Creating an ovpn device and establishing the shared-skb condition requires CAP_NET_ADMIN/CAP_NET_RAW, which an unprivileged user can obtain inside a user namespace (unshare -Urn), so this is Low rather than High.\nUI:N - The bug is triggered purely by transmitting packets through the interface; no victim action is required.\nS:U - The use-after-free is contained within the kernel\u0027s own security authority and does not cross into a different security scope such as a VM or IOMMU boundary.\nC:H - A use-after-free read of the freed skb (protocol, data, len) lets an attacker who controls the reclaimed object contents read sensitive kernel memory.\nI:H - The use-after-free can be leveraged via heap grooming of the freed skb to corrupt kernel state and achieve write/control-flow primitives.\nA:H - Dereferencing the freed skb readily causes a kernel oops/panic, a full denial of service."
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    "datePublished": "2026-05-27T12:17:47.891Z",
    "dateReserved": "2026-05-13T15:03:33.086Z",
    "dateUpdated": "2026-08-05T12:28:44.254Z",
    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.